Relay or Switching Circuit:
GROUNDED SWITCHING
Most transceivers employ a grounded circuit to
switch from the receive to the transmit position. To
connect the microphone to such a circuit, proceed
as follows.
1. Unscrew the two screws securing the micro-
phone baseplate, and remove the baseplate.
2. Cut the GRAY lead connecting two terminals of
the press-to-talk switch (see Figure 1).
3.
Reassemble the baseplate to the microphone and
fasten securely with the previously removed
screws.
4.
At the end of the cable, connect the RED lead
to the terminal used to complete the transmitter
circuit.
5. Connect the BLACK lead to the terminal used to
complete the receiver circuit. This will usually
be a ground return from the loudspeaker. If a mi-
crophone switching contact is not required for
the loudspeaker ground, insulate (wrap with
tape) the BLACK cable lead.
6. Connect the shield to chassis or circuit ground
of the transceiver (see Guide).
ISOLATED SWITCHING
In some transceivers, an isolated circuit is required
to switch power supply voltages rather than grounds.
If an isolated switching circuit is required, proceed
as follows.
1. Unscrew the two screws securing the micro-
phone baseplate, and remove the baseplate.
2. Clip and insulate the BLUE lead from the press-
to-talk switch to the ground lug (see Figure 1).
3.
Reassemble the baseplate to the microphone
and fasten securely with the previously removed
screws.
4.
At the end of the cable, connect the RED lead to
the isolated switch contact terminal used to
complete the transmitter circuit.
5. Connect the BLACK lead to the other isolated
switch contact terminal used for power supply
voltage.
6. Connect the shield to chassis or circuit ground
of the transceiver (see Guide).
CAUTION
Make certain that the shield is not connected to
chassis ground for those models where the Guide spe-
cifies the shield should be connected to circuit ground.
NOTE
In some transceivers, there may be oscillation,
squealing, or low volume in the Receive mode. In any
of these cases, clip and insulate the WHITE lead
between the printed circuit assembly and the normally
closed contact of the press-to-talk switch (see Fig-
ure
1).
Microphone Audio Input Circuit:
Connect the WHITE cable lead to the microphone
audio input terminal.
VOLUME CONTROL
When the 526T replaces a ceramic (usually high-
impedance) microphone supplied as original equip-
ment, the volume control should be set at the lower
ranges to prevent overmodulation and unintelligible
transmission. Correct modulation can be checked on
the modulation level indicator.
When the 526T replaces a dynamic (usually low-
impedance) microphone supplied as original equip-
ment, the volume control should be set at the upper
ranges for correct modulation as indicated on the
modulation level indicator.
VOX OPERATION
Most amateur equipment and some CB transceivers
are designed for either press-to-talk or VOX (voice-
operated relay) operation. The Model 526T provides
for operation in either mode by use of the NORMAL/
VOX slide switch on the bottom of the microphone
base.
For press-to-talk operation, the slide switch should
be in the NORMAL position. For VOX operation, the
switch should be in the VOX position with the control
bar locked in the On position.
LOCKING PRESS-TO-TALK SWITCH
The fingertip control bar of the press-to-talk switch
can be used in a momentary or locked-on position. For
use as a momentary switch, depress the control bar
and release after transmission. To lock the switch in
the On position, depress the control bar and move it
forward with the fingertips. To unlock the switch, move
the control bar backward and remove pressure.
SPECIFICATIONS
TYpe
Dynamic (with transistor preamplifier)
Frequency Response
200 to 6,000
Hz
(see Figure
2)
TYPICAL
FREQUENCY
RESPONSE
FIGURE
2
Polar Pattern
Omnidirectional
Output Impedance
5,000
ohms
